The invention relates to a set of switches with means of mutual locking comprising three switches, where each switch has actuation means connected via cables with locking means.
Known means of actuation stretch the cables when passing from the switch open position to the switch closed position. Known means of locking, actuated by the cables, prevent closure of the switch.
It is known that in an electrical plant consisting of two separately fed systems of bars, one switch is inserted into each system of bars. A third switch is inserted into a system of bars for linking the first two systems, and is normally open. In the event that one of the feeds fails, the switch, which connects this feed to the system of bars of the electrical plant, opens and the third switch, which connects the two systems of bars (or linking switch), closes connecting the remaining active feed to both systems of bars.
The device for mechanically interlocking the three switches guarantees that the two feeds are not inadvertently connected together when they are both active and connected to the electrical plant.
At present mechanical interlocking between three switches is carried out by connecting to known means of locking of known mechanisms. These mechanisms, present on each of the switches, are connected by first movable parts to the known means of actuation of the other switches via known flexible cables. Second movable parts of the mechanisms are connected to the known means of locking of the switch.
The first movable parts, usually consisting of slides, guided for example by pins running in suitable slots, transmit the motion imposed by the actuation means to the second movable parts. This transmission takes place by virtue of guide channels. Channels made between the first movable parts. The geometries of these guide channels can be altered with the relative position of the movable parts.
Only in the case in which two of the switches are simultaneously closed, these first movable parts, connected to them, restrict the guide channels in a manner appropriate for anchoring and dragging the second movable parts. In their turn these second movable parts transmit the motion to the switch locking mechanisms.
These mechanisms are bulky, complex and made up of a large number of components. In particular these mechanisms are sensitive to the correct magnitude of the dimensional tolerance of the various parts for effecting functioning.
Additionally, correct mounting of the components of the mechanism on the switch considerably influences functioning.